Indiana’s Longest Cave System Extended 

Explorers push endurance limits to push the cave to the 40-mile mark.

When they emerged from the cave to the darkness of a predawn Indiana cornfield on July 13th, 11 cave explorers knew they had pushed their own endurance limits to propel Corydon Indiana’s Binkley Cave system over the 40-mile mark.

Muddy, wet, weary but smiling cavers with the Indiana Speleological Survey (ISS) arrived back on the surface after a 17 plus hour trip which added over 7,700 feet of new passage. Pushing their limits, they also pushed the surveyed length of the cave became 40.65 miles,

The group’s objective for their recent trip was to survey enough of the underground river passage found on June 14th
reach the elite 40-mile mark. While there are a number of US caves between 30 and 40 miles in length, there are only three caves between 40 miles and 100 miles in length. On their previous trip, they had turned around in the enormous new river passage that cave explorers described as “chugging off into the darkness”.

All of the new surveys were in a large “borehole” passage that no human had ever set foot in until now. The new passage was named the “McLain River” in honor of ISS caver, Tim McLain, who died of a heart attack in another part of the cave last year. Cavers followed a booming passage teeming with cavefish and crayfish onward through two large rooms to the rise of the McLain River – a beautiful blue pool. Here the river flows up and out of a water-filled conduit that will require high specialized caving diving to continue exploration in this direction.

The weary cavers reported seeing several large side passages that were not explored. In addition, the downstream portion of McLain’s River has barely been entered. Team members all agreed that there is much more cave to be discovered and surveyed in this portion of the Binkley Cave system.

Binkley Cave has been growing rapidly since long-time ISS caver Gary Roberson published a history of the cave’s exploration Fifty Years Under the Sinkhole Plain in 2009. At the time of publication, Binkley Cave was just over 22 miles in length. It has almost doubled over the past five years. Major breakthroughs and breathtaking discoveries have come almost one after the other over this five-year span.

One of these new discoveries was the Indiana Caverns section found in the fall of 2010. Indiana Caverns, which features ice age bones, a 35-foot waterfall, and an underground boat ride, opened to the public in June 2013 giving non-cavers their first glimpse of the underground cavern hidden below Harrison County’s sinkhole plain while dressed in street clothes.

Rand Heazlitt, a long-time ISS member and part of the Indiana Caverns development team, pushed a 1700-foot long water crawl on his first caving trip after completion of the cavern development project to discover the path leading to this vast new section known as the Wild Wild West. With this discovery, the cave broke out into a huge new area of the sinkhole (karst) plain south of Corydon.

The discoveries of the past year indicate that over time the Binkley Cave system has the potential to possibly grow to over 100 miles in length and become one the truly great caves of the world. The cave system is currently the longest in Indiana, the 9th longest in the US, and the 40th jump up into 8th longest in the world. The cavers said they need only about 200 feet of a new survey to place in the US. That undoubtedly will occur on their next trip.